In the following discussion large complex industrial fires comprise the paradigmatic fires of interest. The burning of petrochemical storage tanks or tanker ships offer examples of such a large complex fires.
The so-called three dimensional fire, or a fire fed by a remote replenishing source, presents a fire fighter with a particularly troublesome scenario. The apparatus and method of the present invention are appropriate for attacking three dimensional fires in a complex industrial context. It is anticipated that the apparatus and method, however, have applications in many other fire extinguishing situations.
Method and apparatus for extinguishing fires using water, water fog and water foam mixtures are well known. Such method and apparatus are discussed and disclosed, for instance, in the inventor's U.S. Pat. Nos. 4,640,461, 4,497,442, 4,828,038, 4,705,405, 4,781,467 and 5,012,969.
A liquid and powder method and apparatus for fire fighting was recently determined to exhibit unexpected and startlingly effective results, particularly in fighting large conflagrations. This method and apparatus form the subject of the inventors' U.S.. Pat. No. 5,167,285.
The use of powder to extinguish fires, however, as mentioned above, has certain disadvantages. Powder is relatively expensive and difficult to store and to maintain over a long period of time in its dry particulate form. Further, a powder does not comprise the most desirable agent with which to flood an environment when human life is caught within the fire zone, such as may occur in an airplane crash.
Certain fluids are known for their effective fire fighting capability in a gaseous state, including certain common inert gases such as carbon dioxide and nitrogen. One reason such fluids in their gaseous state, or as vaporized, may be effective is that they may deprive the fire of oxygen, thereby effectively starving a fire to death. Alternately, the vapor or gas might be an effective fire extinguishing agent because it operates as a heat sink, a diluent in suppressing combustion, or inhibits oxidation. In sum, important fire extinguishing effectiveness may be achieved by a gaseous fluid through various operations, both physical and chemical.
Fluids that demonstrate effective fire fighting capability in a gaseous state when applied to a fire may lack some of the disadvantages of powder mentioned above. For instance, such fluids may be easier to store over time and can comprise a more favorable agent for use when human life is caught within the fire.
Attempting to deliver many gaseous or volatile, vaporizable fluids, however, by streaming or throwing the fluid to the fire, such as for a distance of 50 feet or more (which is a desirable distance to maintain from a large conflagration in the interest of managing personnel risk), has proven difficult in the past. As one example, effectively streaming carbon dioxide to a large fire has generally been conceded to be difficult. A blunderbuss type of a horn nozzle has been known for the application. The horn end of the nozzle is several feet long. Unfortunately, the outlet end of the horn must be virtually placed on the fire to effectively deliver the gas, since by the nature of the gas, it quickly diffuses and dissipates when dispensed into the atmosphere. The proximity of the fire fighter to the fire required to so deliver the gas renders the horn almost useless in fighting large fires. As a general matter, for many desirable gases or highly volatile fluids, it has been conceded to be impracticable heretofore to attempt to deliver the fluids to a large fire in sufficient quantities, and with the right timing, to comprise an effective fire fighting technique.
Given the difficulty in delivering many desirable gases or volatile fluids to large fires, a system for teaching the effective use of such fluids together with other fire fighting techniques and agents has also been lacking. The present invention addresses these problems and deficiencies.
The present invention discloses apparatus and method that achieves surprising and unexpected results. Apparatus is disclosed that enhances the effective and efficient delivery of fluids to a fire, including gaseous fluids and highly volatile fluids and/or fluids that vaporize rapidly upon contact with the fire. (These types of fluids, some of them historically difficult to use in streaming applications, are sometimes referred to herein as "gas fluids".) Methods for extinguishing fire by the delivery of a gas fluid to the fire are also disclosed. The effective and efficient results are achieved by delivering a first gas fluid surrounded by a second liquid fluid. The discovery of the effectiveness of such delivery in a quantity, in a state, at a time, and in a combination with other activities, such that the first fluid at the fire can exert a significant fire fighting effect, is novel.
The term "liquid fluid" as used herein is intended to refer to a fluid or fluid mixture that assumes or retains a liquid state under general atmospheric conditions. Such common liquid fluids may comprise water, foam, water and foam, water and foam concentrate, or other liquid fluid mixtures known to have beneficial fire fighting properties. "Fluid" is used herein to refer to a substance in its liquid or gaseous state.
It is believed that the success of the invention is due in part to multiple synergistic effects experienced in the simultaneous delivery and application to a fire of a first fluid surrounded by a liquid fluid. For instance, the simultaneous delivery process, wherein a first fluid is delivered through the atmosphere within the envelope of a liquid fluid, may itself enhance the fire fighting effectiveness of both fluids. The liquid fluid envelope may not only enhance the streaming of an enclosed fluid or gas, it may permit the shaping and directing of the placement of the first fluid over the fire. The ability to tailor the shape of the envelope allows the area of contact of the first fluid to be controlled, enabling the first fluid to be applied to the totality of a targeted fire area. This marks a noted improvement over present art experience that may include shooting a hole in a fire through too narrow of an application of a gas fluid. The envelope may also enhance the retention of any first fluid upon the fire. Further, the first fluid, or a portion thereof, may become entrained within the liquid fluid envelope, or a portion thereof, during the delivery process. This entraining may enhance the delivery of the first fluid. The entraining may also enhance the retention of the first fluid at the fire after delivery. Also, the first fluid, especially if a volatile liquid, by its expansion, agitation and/or entrainment after discharge from its orifice, may enhance the foaming of the liquid foam mixture envelope during delivery. This assumes that the second fluid is capable of enhanced foaming. Enhanced foam usually improves the fire fighting capability of a liquid foam mixture.